ber of customers who enter a supermarket each hour is normally distributed with a mean of 640 and a standard deviation of 170 What is the probability that the total number of customers who enter the supermarket in one day is greater than 12500? (Hint:

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Assume that the traffic to the web site of Smiley’s People, Inc., which sells customized T-shirts, follows a normal distribution, with a mean of 4.6 million visitors per day and a standard deviation of 880,000 visitors per day. What is the probability that the web site has between 3 million and 4 million visitors in a single day? If needed, round your answer to four decimal digits.

Customers at a popular restaurant spend on average $32.30 per person. Assume that the amount spent follows approximately a normal distribution with a standard deviation of $5.25. What is the probability that a randomly selected customer will spend more than $40.00? • Below what cost do the 20% of customers paying the least spend?

company that owns a large number of grocery stores claims that customers who pay by personal check spend an average of $87 with a standard deviation of $22.  Assume the amount spent by these customers is normally distributed. What is the probability that a customer spends more than $100? Express your answer as a decimal rounded to four places after the decimal point.

At night, John works occasionally as a waiter for his family's restaurant for which his monthly income is normally distributed with a mean of $1,579 and a standard deviation of $103. What is the probability that John will earn between $1,322 and $1,764 this month? (Keep 4 decimal places).

Assume that adults have IQ scores that are normally distributed with a mean of95.4 and a standard deviation of 16.6. Find the probability that a randomly selected adult has an IQ greater than 118.1 The probability that a randomly selected adult from this group has an IQ greater than 118.1 is what?

Full-time college students report spending a mean of 23 hours per week on academic​ activities, both inside and outside the classroom. Assume the standard deviation of time spent on academic activities is 3 hours. Complete parts​ (a) through​ (d) below.       a. If you select a random sample of 16 ​full-time college​ students, what is the probability that the mean time spent on academic activities is at least 22 hours per​ week? ​(Round to four decimal places as​ needed.)     b. If you select a random sample of 16 ​full-time college​ students, there is an 89​% chance that the sample mean is less than how many hours per​ week?  ​(Round to two decimal places as​ needed.)   c. What assumption must you make in order to solve​ (a) and​ (b)?   A. The population is uniformly distributed.   B. The sample is symmetrically​ distributed, such that the Central Limit Theorem will likely hold.   C. The population is symmetrically​ distributed, such that the Central Limit Theorem will…

r a standardized psychology examination intended for psychology majors, the historical data show that scores have a mean of  510  and a standard deviation of  170 . The grading process of this year's exam has just begun. The average score of the  40  exams graded so far is  526 . What is the probability that a sample of  40  exams will have a mean score of  526  or more if the exam scores follow the same distribution as in the past? Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.